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MODEL IDbytedance:seedream@5.5

Seedream 5.5

ByteDance
by

Seedream 5.5 is ByteDance's image generation and editing model, focused on visual realism, aesthetics and editing consistency. It supports text-to-image and reference-guided editing with up to 10 input images, keeps unedited areas stable across multi-turn edits, and outputs transparent images from a prompt or from references. It can also split an image into a base image and up to 99 editable layers, returning the text, position, font and style of each text layer, which suits poster, packaging and marketing design workflows.

Seedream 5.5

API Options

Platform-level options for task execution and delivery.

taskType

stringrequiredvalue: imageInference

Identifier for the type of task being performed.

taskUUID

stringrequiredUUID v4

UUID v4 identifier for tracking tasks and matching async responses. Must be unique per task.

outputType

stringdefault: URL

Image output type.

Allowed values3 values

outputFormat

stringdefault: JPG

Specifies the file format of the generated output. The available values depend on the task type and the specific model's capabilities.

  • `JPG`: Best for photorealistic images with smaller file sizes (no transparency).
  • `PNG`: Lossless compression, supports high quality and transparency (alpha channel).
  • `WEBP`: Modern format providing superior compression and transparency support.
**Transparency**: If you are using features like background removal or LayerDiffuse that require transparency, you must select a format that supports an alpha channel (e.g., `PNG`, `WEBP`, `TIFF`). `JPG` does not support transparency.
Allowed values3 values

outputQuality

integermin: 20max: 99default: 95

Compression quality of the output. Higher values preserve quality but increase file size.

webhookURL

stringuri

Webhook URL that receives JSON responses via HTTP POST when generation tasks complete. For batch requests with multiple results, each completed item triggers a separate webhook call as it becomes available.

Learn more1 resource

deliveryMethod

stringdefault: sync

Determines how the API delivers task results.

Allowed values2 values
Returns results directly in the API response. Over HTTP, a task still running after 120 seconds continues as an async task and comes back with status 'processing'. Poll for its results using getResponse.
Returns an immediate acknowledgment with the task UUID. Poll for results using getResponse.
Learn more1 resource

Specifies a URL where the generated content will be automatically uploaded using the HTTP PUT method. The raw binary data of the media file is sent directly as the request body. For secure uploads to cloud storage, use presigned URLs that include temporary authentication credentials.

Common use cases:

  • Cloud storage: Upload directly to S3 buckets, Google Cloud Storage, or Azure Blob Storage using presigned URLs.
  • CDN integration: Upload to content delivery networks for immediate distribution.
// S3 presigned URL for secure upload
https://your-bucket.s3.amazonaws.com/generated/content.mp4?X-Amz-Signature=abc123&X-Amz-Expires=3600

// Google Cloud Storage presigned URL
https://storage.googleapis.com/your-bucket/content.jpg?X-Goog-Signature=xyz789

// Custom storage endpoint
https://storage.example.com/uploads/generated-image.jpg

The content data will be sent as the request body to the specified URL when generation is complete.

safety

object

Content safety checking configuration for image generation.

Properties1 property
safety » checkContent

Enable or disable content safety checking. Increases total generation time.

ttl

integermin: 60

Time-to-live (TTL) in seconds for generated content. Only applies when outputType is URL.

Include task cost in the response.

numberResults

integermin: 1max: 20default: 1

Number of results to generate. Each result uses a different seed, producing variations of the same parameters.

Inputs

Input resources for the task (images, audio, etc). These must be nested inside the inputs object.

inputs » referenceImages

referenceImages

array of stringsmin items: 1max items: 105 limits

List of reference images (UUID, URL, Data URI, or Base64).

Core Parameters

Primary parameters that define the task output.

model

stringrequiredvalue: bytedance:seedream@5.5

Send auto instead of an AIR identifier to have the model router choose the model for this task. The rest of the request is unchanged, every value you send is kept, and only the parameters you leave out are filled in. See Model Router.

Learn more3 resources

positivePrompt

stringrequired*min: 1

Text prompt describing elements to include in the generated output.

Learn more1 resource

width

integermin: 256max: 16383

Width of the generated media in pixels.

Learn more2 resources

height

integermin: 256max: 16383

Height of the generated media in pixels.

Learn more2 resources

Resolution preset for the output. When used with input media, automatically matches the aspect ratio from the input. Without a reference image, the model picks the aspect ratio from the prompt.

Allowed values3 values

Settings

Technical parameters to fine-tune the inference process. These must be nested inside the settings object.

settings » background

Background handling in generated images.

Allowed values3 values
Decided by the model from the prompt and outputFormat, always opaque for JPG output.
Transparent background.
Solid background, no transparency.
settings » layerDecomposition

Enables layer decomposition of the reference image. The layers are returned in outputs.layers next to the base image. outputFormat applies to the base image only, layers are always PNG.

settings » layerDecompositionMaxImages

layerDecompositionMaxImages

integermin: 2max: 100

Maximum number of images layer decomposition returns, base image included.

settings » layerDecompositionTextRecognition

Rich-text OCR for the layers the model recognizes as text, returned in outputs.layers[].textRecognition.

settings » safetyIdentifier

safetyIdentifier

stringmin: 1max: 64

Identifier of the end user, used by the provider to detect usage-policy violations. Must stay the same for a given user.

Features

Standalone addons and post-processing features.

advancedFeatures » watermark

watermark

object

Configuration object for adding watermarks to generated videos. Watermarks can be applied using either text or image content with customizable positioning and appearance. You must provide either text or image content for the watermark, but not both.

"advancedFeatures": {
  "watermark": {
    "text": "© 2025 Company",
    "displayPosition": "bottom-right",
    "opacity": 0.6,
    "fontColor": "#ffffff",
    "bgColor": "#000000"
  }
}
"advancedFeatures": {
  "watermark": {
    "image": "c64351d5-4c59-42f7-95e1-eace013eddab",
    "displayPosition": "top-left",
    "opacity": 0.6
  }
}
"advancedFeatures": {
  "watermark": {
    "text": "PREVIEW",
    "tiled": true,
    "opacity": 0.4,
    "fontColor": "#cccccc"
  }
}
Properties6 properties
advancedFeatures » watermark » text

text

stringmin: 2max: 32

Watermark text.

advancedFeatures » watermark » image

image

string

Watermark image (UUID, URL, Data URI, or Base64).

advancedFeatures » watermark » displayPosition

Watermark position.

Allowed values10 values
advancedFeatures » watermark » opacity

opacity

floatmin: 0.1max: 1step: 0.01

Watermark opacity.

advancedFeatures » watermark » fontColor

fontColor

string

Text color in hex format.

advancedFeatures » watermark » bgColor

bgColor

string

Background color in hex format.